The present invention relates to an amplified solid-state image pickup device and an image pickup system using the same.
A solid-state image pickup device including a plurality of pixels, each being an amplified MOS image sensor called “AMI (amplified MOS imager)”, has been known in the art. Each pixel includes a photodiode for converting incident light into an electric charge, and a source follower transistor for supplying a signal voltage according to the amount of charge generated by the conversion.
A conventional technique achieves a high frame rate by dividing the image pickup area of MOS image sensors into a plurality of blocks, and repeatedly scanning only pixels in at least one block being selected (see Japanese Laid-Open Patent Publication No. 4-277986).
For image pickup systems such as digital still cameras and digital video cameras, there is an increasing demand for rapidly shooting a series of frames with a high resolution and for taking a motion picture with a high resolution.
One way to rapidly take an high-resolution image with an image pickup system using an amplified solid-state image pickup device is to divide the image pickup area into a plurality of blocks while providing an output amplifier for each of these blocks. However, with such an amplified solid-state image pickup device of a parallel output type, characteristic variations inevitably occur among the output amplifiers. Therefore, it is necessary to correct the gray level variations among the amplifier outputs, and this level correction needs to be a non-linear correction.